1. Field of the Invention
The present invention relates to a method and a device of audio source separation, and more particularly, to a method and a device of audio source separation capable of being adaptive to a spatial variation of a target signal.
2. Description of the Prior Art
Speech input/recognition is widely exploited in electronic products such as mobile phones, and multiple microphones are usually utilized to enhance performance of speech recognition. In a speech recognition system with multiple microphones, an adaptive beamformer technology is utilized to perform spatial filtering to enhance audio/speech signals from a specific direction, so as to perform speech recognition on the audio/speech signals from the specific direction. An estimation of direction-of-arrival (DoA) corresponding to the audio source is required to obtain or modify a steering direction of the adaptive beamformer. A disadvantage of the adaptive beamformer is that the steering direction of the adaptive beamformer is likely incorrect due to a DoA estimation error. In addition, a constrained blind source separation (CBSS) method is proposed in the art to generate the demixing matrix, which is able/utilized to separate a plurality of audio sources from signals received by a microphone array. The CBSS method is also able to solve a permutation problem among the separated sources of a conventional blind source separation (BSS) method. However, a constraint of the CBSS method in the art is not able to be adaptive to a spatial variation of the target signal(s), which degrades performance of target source separation. Therefore, it is necessary to improve the prior art.